The experimental and clinical research projects comprising this program maintain the interdisciplinary studies of inflammatory bowel disease. The clinical projects continue to develop baseline demographic information on the patient population with inflammatory bowel disease. The clinical studies also emphasize the familial occurrences of inflammatory bowel disease, and a variety of complicating and associated medical problems. Study of growth retardation in children with inflammatory bowel disease has continued. A significant development has been the creation of a diagnostic review board, comprised of gastroenterologists, pathologist and radiologists, wherein diagnostic problems are reviewed with particular reference to ulcerative colitis versus regional enteritis of the colon. Another important development is recognition of the frequent occurrence of folate deficiency in patients with inflammatory bowel disease and the apparently causative role of Azulfidine. The double-blind controlled studies with Imuran continue, and definitive data are anticipated during the forthcoming year. An additional controlled evaluation of parenteral alimentation in the treatment of inflammatory bowel disease has begun. The experimental studies include continuing investigations of rectal cell karyotyping in inflammatory bowel disease and in cancer of the colon and rectum; the status of the liver and the bile salt metabolism in vitro studies of intestinal and colonic epithelial cell, and immunologic studies directed especially to the central role of the gastrointestinal tract in immunologic homeostasis and to the immunologic behavior of circulating lymphocytes in patients with inflammatory bowel disease and other disorders.